Bit lock



'Sept 23, 1930' J. M. BOYD 1,776,280

BIT LOCK Filed Nov. 19..'1927 In en or Jam f7. 305/09 Allorney PatentedSept. 23, 1930 UNITED STATES :roi-:N M. BOYD7 or SEATTLE, WASHINGTON BITLOCK Application filed November 19, 1927. Serial No. 234,341.71;` y

end of the drilling tool and prevent the bit from becoming loosened,thereby preventing loss of the bit. v

In carrying out my invention, l provide ra locking bolt that is adaptedto lock the bit to the drill rod after the former has been screwed tothe latter, and means jare pro'- vided whereby the retaining` bolt maywith facility be withdrawn in order that the bit may be unscrewed fromthe rod when deired.

The invention consists in certain novel combinations and arrangements ofparts as will hereinafter be more fully pointed out and claimed.

ln the accompanying drawings, l have illustrated one complete example ofthe physical embodiment of my invention wherein the parts are combinedand arranged according to the best Inode I have so far devised for thepractical application of the principles of my invention.

Figure 1 is a view in elevation at the lower end of an earth boring ordrilling tool showing the use of the device of my invention;

Fig. 2 is an enlarged detail vertical sectional view at line 22 of Fig.1 showing the bit locked on the lower end of the drill rod;

Fig. 8 is a View similar to Fig. 2V but with the locking bolt withdrawnand the bit re- 1eased so that it may be nnscrewed;

4 is an enlarged detail view as at line 4--4 of Fig. 2;

Fig. 5 is a perspective view of the spring pressed locking bolt; and

Fig. 6 is an enlarged perspective view of the lever for the bolt.

In order that the general'arrangement and relation of parts may readilybe understood, l have shown in Fig. 1 a well known type PTNT "oFF- icsOfbit as 1 :having a vshank 2 vwhich isyse- A cured tothe rod or tool 3.The shank is provided with the usual tapered threaded head 4 andthisisscrewed into 'the complementary socket head 5 Onthelower endof ythetool. Thefprimary Object of`1ny-invention is to prevent the lthreadedhead 4 from becoming `imscrewed from thesocket head, and to this end lemploy a spring pressed b olt16 located at. one side j, of thelongitudinal center of the-tool` and .normallycarriedin theV sockethead.n. y i Y.

y AThe bit shank ,-2 is lfashioned withpseveral sockets indicated as'"7in Fig. 4, and one of these sockets is adapted to receive the bolt 6 asindicated. The bolt is carried in a recess 8 in the socket head 5 and aspring 9 in this Vrecess bears against thespring bolt 6 and tends toforce it from its socket 8 into the socket 7 in the bit shank. In lockedposition as in Fig. 2, the spring retains the bolt in the socket 7 andthe bit is thus prevented from turning with relation to the socket head5.

To withdraw the bolt from its socket 7 I provide a lever 10 whichnormally lies in a i groove 11 in the exterior face of the socket head5, and this lever coacts with the spring l bolt 6 which is provided witha longitudinal slot 12. The spring bolt is equipped with a pin 13 thatextends transversely through the l bolt and through the slot 12, and thelever 10 is` provided with a curved arm 14 of proper width to iit withinthe slot 12. arm 14 lits around the pin 13 and the shoulders 15 of thelever at the sides of the arm 14 prevent -excess movement ofthe lever.As shown in Fig. 2, the lever 10 lies in the groove 11 and its angulararm'14 engages the pin 13. r1`he angular arm 14 projects through atransverse slot 16 in the socket head and the bent portion of the lever10Y bears against the bottom wall of this slot 16 as the fulcrum whenthelever is turned to-withdraw the bolt 6. In F ig. 3, it will be seen thatthe lever has been swung outwardly to withdraw the bolt, in order thatthe bitmay be unscrewed from the socket head. As soon as the lever 10 isreleased, the spring 9 bearing against the spring bolt quickly moves theThis curved bolt and swings the lever 10 into itsgroove 11 in order tohold the lever in position.

The lever 10 may be turned by slipping the thumb-nail or a sharp edgetool under the free end of the lever to give it the initial movement andthen it may be swung by hand to rele-ase the spring bolt. After release,the lever lO'is automatically returned to its groove l1 by action of thespring 9. e

Having thus fully described my invention,

what I claim as new and desire to seeure'by Letters Patent is Thecombination with a bit having a boltY socket and a threaded head, oacomplementary nteriorly threaded socket head receiving the threadedheaehsaid socket head havfing an exterior groove and transverse slot,

' a spring-pressed bolt in said socket head eooperating with the boltsocket and provided i with a longitudinal slot, a transverse pin in vthebolt-slot, an L-sha-ped lever having a curved end looselyengaging saidpin and adapted to lie'in the' groove, and lateral stop shoulders en thelever adapted to engage the bolt, whereby said lever co-operates withthe bottom wall of the-transverse slot to acta-s a fulerum when thelever is turned,

VIn testimony whereo vaffix my signa-ture.

JOHN M. Born.

